Is the 'Heaven' in Miner's Heaven meant literally?

Solution 1:

Just to say about the portal placement, it will always return to the same spot, the portals don't work like nether portals it is just one location, confirmed by users on the site you linked. This is not intentional and the mod maker is looking into it.

an example

Nice mod. I set everything up went poof to the Mining world and returned. Decided I did not like the placement of my source portal so I moved it. However everytime I return I return to the place it used to be. Is there a way to change where I return?

I have checked the change logs and as yet there is no fix for this.

Chances are you have spawned in the wall, you will need to dig until you find a cave network, I would say dig straight down (with caution) as i believe there is no surface.